The present invention relates to an integrated circuit for monitoring a power supply voltage, and particularly to an integrated circuit suitably used for an electronic control unit for vehicle brake control.
An electronic control unit (ECU) has a power output circuit which is monitored and a power supply monitoring unit. which monitors a power output. The power supply voltage is supplied to a plurality of circuit blocks within the ECU having the power output circuit and the power supply monitoring unit monitors whether an output Voltage of the power output circuit is set to a predetermined voltage value or not.
The power output circuit and power supply monitoring unit are connected to an external power supply via only one power supply terminal provided in the ECU. The power output circuit generates, on the basis of a voltage applied to the power supply terminal, a reference voltage supplied to a plurality of circuit blocks and a reference voltage used by the power supply monitoring unit to monitor the output voltage of the power output circuit.
However, the power output circuit and the power supply monitoring unit are provided on different chips, resulting in an increased manufacturing cost of the electronic control unit and an enlarged installation area of the ECU.
It is therefore an object of the present invention to provide an integrated circuit for monitoring an output voltage of a power output circuit with only one chip.
According to the present invention, an electronic control unit for a vehicle such as an ABS control ECU includes an integrated circuit, which comprises a monitored block for supplying a power supply voltage to other circuits and a monitoring block for monitoring the monitored block. The monitoring block and the monitored block are formed on the same chip. Further, power supply terminals for supplying voltages to the monitored block and the monitoring block are provided as different terminals. Ground terminals for the monitored block and the monitoring block are also provided as different terminals.
Preferably, the monitored block and the monitoring block are arranged as spatially separated blocks in the same chip. The monitored block and the monitoring block are insulated and isolated in the same chip. The monitored block and the monitoring block are, formed on a SOI substrate, and the monitored block and the monitoring block are insulated and isolated with a trench formed on the SOI substrate. Reference voltage generating circuits of the monitored block and the monitoring block are formed in different circuit configurations from each other.